Best practice for UV mapping buildings from CAD software
I used to do this kind of UV mapping a bit and found 3 methods useful.


UV Project modifier, you can use a camera for each wall angle and the cameras project onto the closest aligned walls. very fast to setup and you can edit your geometry afterwards without having to fix UV's.
Smart UV project, this gives simple projections but has the disadvantage that the bricks on the walls for example, wont line up.
Manually - which can be done quite fast infact - Select a face, Shift+G, Select Similar Normal. Then project from view, or from a Camera if you want to have more control over alignment and quickly re-apply the same projection again can be handy too.


Other things to be aware of...


You may want to move the projected UV's for each surface so they dont overlap.(just makes it easier to edit and manage). with tiling textures it wont effect the displayed mapping on the mesh.
topology may be important to improve, this depends weather you are simply projecting UV's or if you intend to manually edit them (in that case you care more about topology and avoid skinny faces for example).